Automatic radio tuner



Jan. 2, 1945.

J. L. SWALLOW. 2,366,573

1 AUTOMATIC RADIO TUNER Filed July 16, 1942 5 Sheets-Sheet l %M dmm 9 71 l /azea Jan. 2, 1945. J. L. SWALLOW AUTOMATIC RADIO TUNER Filed July 16,, 1942 5 Sheets-Sheet 2 @ezza x Jan. 2, 1945. sw ow 2,366,573

v AUTOMATIC RADIO TUNER I Filed July 16, 194.2 5 Sheets-Sheet 3 Jan. 2, 19 45. SWALLQW 2,366,573

AUTOMATIC RADIO TUNER Filed July 16, 1942 5 Sheets-Sheet 4 Jan. 2, 1945. J. L. SWALLOW AUTOMATIC RADIO TUNER Filed July 16, 1942 5 Sheets-Sheet 5 Patented Jan. 2, 1945- UNITED STATES PATENT OFFICE.

an'roua'rro mmo roman Joseph 14. Swallow, Lombard, 111., assignor to Wells-Gardner & tion of Illinois 00., Chicago, 111., a corpora- Application July 16, 1942, Serial .hlo. 451,128

7 Claims. (01150 -20) The tuning device ofthe present'invention is designed primarily for use in situations wherein it is desirable to pick up reports or signals in recurrent sequence from a group of stations transmitting upon different frequencies, and in order to' successively bring in these stations provision is made for automatically adjusting the movable plates of the condenser in each case, and for a stated interval, to the required position to bring in the stations in. sequential order;

In the present mechanism it is preferred to employ a constantly and uniformly'rotating cam carrying disk or plate having mounted thereon a group of individually adjustable cam members which afford a. rolling contact for the member which oscillates the shaft carrying the condenserplates, and since the present mechanism must'be capable of continuous and uninterrupted operations over long periods of time it is highly important that the adjustable cam surface shall be of such character as to aflord a smooth and sinuous track uninterrupted by projections or sharp variations in contour which might be subject to wear or excessive friction, and the adjustable cam assembly of the present invention has been dedesigned to meet these requirements and at the same time permit easy and accurate adjustments of the individual cam members.

mechanism showing the adjustable cam assembly at the right and the condenser groups at the left;

Fig. 2 is a perspective view with the casing partly broken away to reveal the interior transmission. mechanism Fig. 3 is a face view of the frequency cam asgo permit substitution of another disk plate;

a further important object of the present in ventlon is to provide adjustable means for timing the intervals of movement and rest of the adjustable cam carrying plate so that each of the sending stations will remain tuned in for a pre- Fig. 8 is a similar view showing the associated parts displaced; 7

Fig.9 is a rear face viewoi thefrequency cam carrying plate showing the mounting for the same;

Fig. 10 is a perspective view of the spur-gear for driving the frequency c'a' 'n carrying disk plate;

and

Fig. 11 is a perspective-details! the coupling for permitting disengagement of the automatic determined interval, as for instance ten seconds,

after which a quick shift will bring the next station of the series into tune. By suitable manual adjustment, the mechanism can be set for a number of dlflerent periods of reception, as forv instance three seconds, four seconds, flve seconds,

etc., up to ten seconds, for reception, with a short intervening interval, as for instance one second, for the readjustment of the condenser.

Provision is also made for disconnecting the automatic adjustment mechanism so that the condensers may be adjusted by manual operation in the usualmanner.

The invention also relates to the power trans,- mlsslon trains employed and tothe means provided for housing and enclosing the operating mechanism within a casing adapted to contain oil for lubricating purposes.

Further objects and details will appear from the description of the invention in conjunction with the accompanying drawings, wherein:

l'lgurc 1 isa perspective view of the entire drive mechanism from the condenser shaft -'to allow for manual adjustment of the condenser.

The automatic adjusting mechanism of the present invention is enclosed within a box-like housing of rectangular stepped formation comprising frontand rear side walls In and II, uP-

per and lower inner end walls l2 and 13 stand-- ing in stepped arrangement, an outer end wall I of full height, an upper cover wall IS, a lower cover wall [6, and a base partition plate I! which elevates the working mechanism above the floor of the housing, thus afiording an oil reservoir in the. base of the housing.

Within the interior of the casing is located a frame which includes a cross partition .plate- I l,

spaced from the outer end wall I, innerand outer longitudinally extending plates l9 and Ila,

and a shelf ilwhich'connects along its edges with the plates II and II, and forms in conjunction therewith an interior mounting for certain of the operating mechanisms presently to be de-' scribed. Theirame' also includes an end plate Ila in spaced relation to the plate 18,. and in abutment-with the wall H, the various portions ottbe frame einsrisl vimlted together. The

end wall and has its inner end mounted withinthe partition plate It. The cam assembly is held in place by a thumb nut 25 on the end of the shaft, which may be removed to permit other cam assemblies having different spacing arrangements to be substituted as occasion may require.

The cam assembly comprises a disk shaped base plate 26having fixedly and concentrically mounted thereon a plurality of' segments 21 of a-lesser radius than .the base plate and spaced from one another to afiord radial grooves or channels 28, which converge inwardly to a collar 29 which is provided with a plurality of notches 30 in its outer edge. .The collar stands in spaced relation to an enlarged head 3| on the end of the shaft 24, as will appear from an inspection of Fig. 9. I The base plate 26 stands in adjacent relation to a stepped disk 31a which is freely mounted on the shaft head 3| and is cut through save at its rim by opposite radially extending slots Bib which are narrowed at their inner ends to clamp the ends of oppositely extending leaf springs 3lc whose free outer ends are free to have limited movement within the surrounding slots. The ends of the leaf springs are looped to receive the ends of pins 3ld projecting from the face of the base plate. The stepped disk 31a has screwed thereto a spur-gear 53 which forms part of the transmission train which drives the cam assembly but the spring connection with the base plate permits the latter to be exactly centered by the a detent mechanism presently to be described. Each of the radial channels 28 aflords a guide way for -a cam carrying stem 32 which, as shown in Fig. 5, is provided with a smooth outer bore 33 merging at its inner end into a threaded bore 34 which receives the threaded end of an adjusting screw 35, provided at its inner end with a head 38 and at its outer end with a cross notch 31 adapted to receive a small screw driver.

' The stem at its outer end is provided with an inwardly extending ear 38 which is rounded on its outer face to afford an easy riding surface,'which ear merges into the rim of a head plate 38 inwardly projecting from the inner face of the stem.

The cams are adapted to be variably adjusted by turning the respective screws 35 to bring the outer ends of the stems with the rounded head plates and cams each to the desired positions to secure the proper tuning for each of the stations, and after the various adjustments have been made the parts are locked in position by means of clamping segments 45, which are held in clamping position by means of screws 46, which are preferably'located in close relation to the respective cam stems, so that when screwed down they will hold the respective cams tightly in relatively adjusted position.

The cam assembly heretofore described is positioned to impart the intended degrees of movement to a roller 41, which is positioned to ride upon the respective cam bars as the cam assembly is intermittently rotated from one position to the next, during the cycle of operations required in bringing each of the stations in turn into tune for a predetermined period of time, the mechanism being actuated in such a way as to impart a relatively quick adjusting movement, during which the contacting cam bar will afford an easy riding surfacefor the roller until the head of the next succeeding cam moves to a position beneath the roller, at which point the movement is arrested for a predetermined period, with the roller standing in such position as to tune in the particular station whose frequency corresponds to the adjustment of the cam head currently in operating position.

In order that each carnhead in turn will be exactly centered during the corresponding tuning period, the edge of the base plate 28' is pro- ,vided with a series of notches 46a. one opposite each cam head, which notches in turn coact with a detent 461) (see Figs. '7, 8) carried at the end of a pivoted arm 4150 drawn inwardly by a spring 46d and since the base plate 26 is permitted to have limited -rotation independently of the hub upon which it is mounted, and of the mechanical driving mechanism which rotatesit by stages The movements imparted to the cam roller 41 I are reflected in the angular adjustment imparted to the outer section 48 of a divided shaft, which also includes an inner section 49 adapted to be clutched'to the outer section through the medium of a manually operated clutch 50 (see Fig. 11);

actuated by a knob 5| within convenient reach of the operator; With theshaftsections clutched together for automatic operation, the angular rotary movements vof the shaft will impart the desired adjustment to gangs of condenser-plates 52 which are carried by the inner shaft section,

4|. to straddle the edge ofthe-head plate upon which it is pivoted by a pintle 42. The free end 43 of the can: bar is of reduced thickness and offset inwardly with respect to the longitudinal center of its pivoted inner end, so that its outer I face will substantiallyallgn with the :inner face of the head plate 39. The opposite end of the head plate carries a grooved stud (which-is positioned to receive the free end of the next ad'- and operate in the usual manner to tune in stations-of different frequencies.

As shown inFig. 11 the outershai't section 4. mounts a spring backed sleev 48a which is slotted to receive a fin 48b outwardly extending from the shaft so that the parts will rotate in unison while permitting sliding adjustment of the sleeve which is effected by rotation of the knob 5| at the outer end of the transverse shaft ila which at its inner end carries a finger Ill) bearing against the face of a flange ring ilc at the outer end of the sleeve "a and which is backed by a spring [Id abutting against a collar ile pinned to the shaft section 48. The sleeve at its inner end carries an arm Ilj provided with a finger Ila which when the shaft section are in clutch freely enters a notch 4st in-a clutch head 50a, being held snugly against the face of the notch which receives the driving thrust by the upper finger of a bell crank 50b, the lower finger of which is drawn back by a spring 500. This ar- -The clutch head 50a is fast on the inner shaft section which connects'with the condenser, but to 'ensure instant automatic setting of the condenser shaft after manual operation, the clutch head is provided with a throated cam face 50d which when the sleeve 48a is free to move under the thrust of the spring 5ld will force the rounded end ofthe finger Sig against the throated cam face and cam the condenser shaft section around until it comes into correct register with the position imparted to the shaft section 48 by the currently active cam head on the base plate 26 at which point the finger will slip into the notch 49a in the clutch head and hold the parts in register as automatic operation is resumed.

The means provided for intermittently timing,

the rotation of the cam assembly will now be described: As before stated, the cam assembly is freely mounted upon the fixed journal shaft 24, and the hub 3|- carries a removable spur-gear 53.

The spur-gear is adapted to mesh with a transmission spur-gear 54 carried by a bell crank 55 and in mesh with a spur-gear 56, carried by a Geneva movement shaft 51 which is journalled at its outer end through the frame plate I81: and the end wall l4 and at its inner end within the partition plate i8. r

The shaft 51 carries a star wheel 58 of the conventional type provided with slots 59 in its edge, which are adapted to be engaged by a pin Bil on an arm 6| extending outwardly from a generally cylindrical body block 62 provided with a slot 63.

' The curvature of the body block conforms to the concave curvature of the edges of the star wheel intermediate the slots 59, andthe block is carried by a sleeve 64 which is slidably mounted upon a shaft 65 carrying a coil spring 66 which bears against the block and normally forces the block and associated parts inwardly into such position that the pin 60 will clear the star wheel without imparting rotation thereto.

, In'order to bring the pin 60 into coacting relation with the star wheel, a grooved collar 61 thereby bringing the pin-60 into position to .en-

cage with one of the slots in the star wheel.

The grooved collar 51 has extending therefrom islotted coupling sleeve 16 which coacts with a pin 11 outwardly extending from the shaft 85,

7 so that the coupling with the grooved collar and block 62 will be rotated by the shaft irrespective of the adjustment of the parts thereon. Rotation is imparted to the shaft throughthe Bear reduction train in the gear box 22, through a ratchet faced coupling 65a so that. driving rotation is imparted in one direction only.

a In, order to effect desired ratios in the periods each of the stations for a period of three seconds,

four seconds, or any period up to ten seconds, with intervals of one second between each reception period to allow for the required adjustment. Each of the cams 15 thus has one or more high points or humps I8 which, when the particular cam is brought into proximity with the roller 14,

will engage and move back the roller to effect a momentary engagement, of the pin 60 with one of the star wheel slots 59 to impart a single step of movement to the cam assembly, after which the pin will be disengaged and restored to idle position by the spring 86. The cam assembly will then stand motionless until the operation is repeated, during which the condenser plates will stand in the proper position to afford reception at the desired frequency. Certain of the cams 15 may be provided with two or more humps or projections which will vary the periods of reception in'conformity with any desired ratio.

All of the cams l6 are journalled upon a carrier plate 19, and each'of the cams has connected a bevel pinion '84 on the inner end of a horizontal shaft carrying a knob 86 at its outer end, with an adjacent pointer 81 to indicate the adjustment required. The rotation of the knob serves to impart rotation to the carrier plate to bring the-desired cam 15 into coacting relation with the roller 14 in order to secure radio reception for the de siredperiods of time.

Constant rotation is imparted to each cam 15 of the entire series through the master pinion BI, which is driven by an inner vertical shaft 90,

. which passes upwardly through the tubular shaft 82 and is provided with a worm wheel 9| on its upper end which engages with a worm. 92 on a shaft 93. The latter shaft carries a spur pinion 94 which meshes with a spur pinion 95 splined onto the shaft 65, which is driven at a constant rate by the motor 2| which is preferably a synchronous motor. Accurate centering of the'carrier plate i9 is ensured by the provision of notches 95a in the rimof the plate which coact with a suitable spring detent not shown.

In order to disengage the automatic tuning mechanism, the shaft 5la which carries the knob 5| is provided with an arm- 91 pivoted to the end of a rod, not shown, which actuates suitable clutch mechanism 98, which need not be described in detail, but which serves, when the automatic drive is disengaged, to clutch in a gear train I00,

which permits the dial I III to be operated by a manually controlled knob 102 in the usual manner, it being understood that when the cam assembly is in clutch, the dial will likewise be rotated to afford a visual record displaying the frequency of the station which is tuned in for the time being.

It will be understood that the tuning frequency cam assembly is made removable, so that another one of several cam assemblies may be substituted therefor in order to accommodate different numbers of stations to the receiving or of rotation and rest of the cam assembly, manu- 76 central station; and it will likewise be understood ally operated adjusting means are provided I that the individual frequency cams may be so adjusted as to bring in the same station two or more times during a single cycle of rotation.

In removing and replacing the cam assemblies w it is necessary to temporarily displace certain of the mechanisms which coact with the cam asapin and slot connection I with the wall I of the housing. The slide bar carries three depending fingers I05, I06 and H", and the slide bar is moved by a lever I08 pivoted by a pin and slot ll! to the end of the bar and fulcrumed at 0.

The lower end of the lever. carries a segment I i I provided on its inner edge with a notch I I2 below which the face N3 of the segment is beveled outwardly and is positioned to engage a roller ill on the inner face of a disk 5 carried by a stud shaft H6 (Figs. 2, 10) entered through the end wall of thehousing and provided with a bolt head ll'l adapted to receive a wrench. The bolt shaft carries a spur-gear Ill having a slotted hub i II which receives a pin I projecting outwardly from the shaft and the parts are so disposed that when the bolt shaft is turned in a I clockwise direction (Fig. 7) it will finally engage the lower ends of the lever I and swing the 2 same outwardly until the roller reaches the notch I I2 and this will impart an inward swing to the with the registering contacts will be illuminated during the period of reception.

In practical use it is customary to supply five tuning frequency cam assemblies having respectively 6. 'Z, 8, 9 and 10 cam groups corresponding to station groups consisting of 6, '7, 8, 9 and 10 stations respectively. Where five stations or less are comprised within the group, certain of the above cams can be used when the number of individual cams is equally divisible by the num- .ber of stations desired. For example, where a two station set-up is desired, the cam assembly having six individual cams would be chosen, as it carries the smallest number of cams divisible by 2. a

It will, of course, be understood that the timing cams 16 are individually configured to throwthe pin into the star wheel slot at the properly timed instant to impart a shift in the cam assembly, and that each cam is-also designed to afford a predetermined period of rest for radio reception conformable to the positions indicated for the adjustments of the knob 86.

Operation In the preliminary adjusting of the several tuning cams it will be desirable to tune each of the stations, in by hand until clear reception is attained, and thereupon adjust the corresponding cam stem to the proper position to contact the roller 41 carried-by thearm on the shaft section 48. When proper adjustment is eflected, the

' adjacent clamping screw ll will be turned down to lock the cam in position, and thereafter the next cam will be similarly adjusted and locked until all of the cams have been set to the reupper end of the lever and a sliding movement tothebar I93 moving the parts to the position shown in Fig. 8.

During this movement the finger I05 will engage theupper end of the bell crank 55; the finger I06 will engage the detent arm 46; and the finger llll will engage a pin l2l on the pivoted arm carrying the roller 41 so that the gears, the

detent and the roller will be moved back in unison to the position shown in Fig. 8 against the weight of the roller, and the tension of springs d and I22, which is connected with bell crank 55.. This permits the entire cam assembly, including the stepped disk and spring connection carried thereby, as well as the spur-gear If to be removed as a unit by the mere removal of the thumb, nut 25 on the end of the shaftll. The spur-- gear Ila meshes with a gear I23 on the shaft so that during the clearing cycle of movements the shaft and parts carried thereby will partake of the movement but at the end of the cycle will be restored to their original position, so that the timing order of the mechanism will not be disturbed by the substitution of a new frequency camassembly.

In order to indicate which of the stations is tuned in for the time being an electric bulb (not shown) is provided for each station at a point visible to the operator, and the base plate- 26 on its inner face is provided with a series of movable contacts [.24 arranged in spiral relation 1 and individually located to register with a corresponding series of fixed contacts I25 (Fig. 7) adjacent the face of the plate so that as the cams are intermittently moved to tuning position the corresponding contacts will-be brought into register and the identifying bulb which is in circuit qulred positions to tune in the respective stations in the proper sequence. I

, After the required setting of the tuning cams has been made, the desired timing cam will be turned into position to engage the roller 41 at the required instant, and it power is now applied to the gear train, the mechanism will operate to bring each station into tune for the required period and in the desired sequence. It will be understood that all of the timing cams will be "rotated constantly by the master pinion, but that only one of these cams will function to engage the roller 41, I

when the hump on the selected cam engages the roller 11, the pin ill will move into position to engage the star wheel and impart a momentary quarter movement thereto sufllcient to quickly turn the tuning cam assembly to the next position of adjustment, at which time the pin will disengage from the star wheel, and the radio reception will continue for the intended interval, depending upon the configuration of the timing cam in immediate service. 7

1 The tuning cam mechanism is designed to atford means for easy and accurate adjustment,

- and at the same time to maintain a smooth contact surface of sinuous or undulating character at all times and without any abrupt variations or obstructions which would tend to cause wear in an instrument which is designed for continuous operation through long periods of time. By the use of a synchronous motor, accurate timing will be maintained in conformity with the setting of, the mechanisms, so that tuning to each station at the intended instant will be'eflected.

I claim:

1. In an automatic radio tuner, the combine. tion of a condenser including a group of adlusta'.

ble plates adapted to establish-selective tuning with the members of a group oi stations operating on diflerent wave lengths, power transmission connections for adjusting the plates and adapted to be variably moved, a movable carrier located in proximity to the terminus of said connections distant from the condenser, a group of cam elements mounted, upon the carrier, each adjustable with relation to the terminus of the connections, a member carriedby the connections positioned to be successivelyengaged by each of the cam elements for imparting movements thereto corresponding in degree to the adjustments of the cam elements, means for imparting adjusting movements to the carrier to bring the cam elements successively into coacting relation alternating with periods of rest to permit radio reception, each of thecam elements consisting of a stem adjustable on the carrier, and a cam bar pivoted at its inner end to the outer end of its. stem and having its free end islidably supported upon the outer end of th next adjacent stem to ail'ord a continuous undulatory trackway for the contact of the member carried by the ,DOwer connections irrespective of the adjustments of the individual cam stems.

2. In an automaticradio tuner, the combination of a condenser including a group of adjustable.plates adapted to establish selective tuning with the members of a group of stations operating on different wave lengths, power transmission connections for adjusting the plates and adapted to be variably moved, a rotatable carrier located in proximity to the terminus of said connections distant from the condenser, a group of cam elements mountedupon the carrier, each adjustable with relation to the terminus of the connections, a member carried by theconnections positioned to be successively engaged by each of the cam elements for imparting movements thereto corresponding in degree to the adjustments of the cam elements, means for imparting adjusting movements of rotation to the carrier to bring the cam elements successively into coacting relation alternating with periods of rest to permit radio reception, each of the cam elements consisting of a stem adjustable radially on the carrier, and a cam bar pivoted at its inner end to the outer end of its stem and having its free end slidably supported upon the outer end tion of a condenser including a group-of adjustamounting carrying a group of diflerently configured cams, means for rotating all of the cams in unison, and manually operable connections to bring any selected cam of the group into coasting relation with the carrier moving means.

4. In an automatic radio tuner, the. combination 01 a condenser including a group of adjustable plates adapted to establish selective tuning with the members of a group of stations operating on difierent wave lengths, power transmission connections for adjusting the plates and adapted to be variably moved, a movable carrier located in proximity to the terminus of said connections distant from the condenser, a group of cam elements mounted upon the carrier, each adjustable with relation to the terminus of the connections, a member carried by the connections positioned to be successively engaged by each of the cam elements for imparting movements thereto corresponding in degree to the adjustments of the cam e1ements,'means for imparting adjusting movements to the carrier to bring the cam elements successively into coacting relation alternating with periods of rest to permit radio reception, means for variably timing the periods of movement and rest or said carrier moving means, said means including a turntable mounting thereon a group of differently configured cams, means for rotating all of the cams in unison, and manually operable connections to bring any selected cam of the group into coacting relation with the carrier moving means, and the carrier moving means including a star wheel in train with" the carrier,

a constantly rotating member adapted to be bis plates adapted to establish selective tuning with the members of a group of stations operating on different wave lengths, power transmission connections for adjusting the plates and adapted to be variably moved, a movable carrier located in proximity to the terminus of said connections distant from the condenser, a group of reception, means for variably timing the periods of movement and rest of said carrier moving means; said means including an adjustable cam elements mounted upon the carrier, 'each moved to position to engage and actuate the star wheel, and connections positioned to be contacted by the coacting cam for moving the rotating member intomomentary engagement with the star wheel to eifect readjustment of the carrier.

5. In an automatic radio tuner, the combination of a condenser including a movable element adapted to establish selective tuning with the members of a group oi stations operating on different-wave lengths, a rotatable power transmission connection with said movable condenser element adapted to be variablyrotated and terminating in an eccentrically mounted roller, a group of individually adjustable cam members each adapted in turn to engage and move said roller in an amount corresponding with the setting of each of said adjustable members, a rotatable carrier tor the group of adjustable members, means including gearing and a Geneva movement for rotating said carrier to bring said adjustable members successively into coacting relation with said roller, andan adjustable member adapted when moved to displace said roller and said gearing to permit convenient removal ofsaid carrier.

6. In an automatic radio tuner, the combination of a condenser including a movable element adapted to establish selective tuning with the members or a group of stations operating on different wave lengths, a rotatable power transmission connection with said movable condenser element adapted to be variably rotated and terminating in an eccentrically mounted roller, a group of individually adjustable cam members each adapted in turn to engage and move said roller in an amount corresponding with the setting of each of said adjustable members, a rotatable carroller, an adjustable member adapted when moved to displace said roller andsaid gearing to permityconvenient removal or said carrier, a lever connected with said member, a rotatable disk having a member adapted to engage and move said lever and adapted to? permit restoration thereof; to its initial position after a cycle of movement, and transmission gearing in train between said disk; and the Geneva movement and adapted at the conclusion or a cycle or movement of 'saiddisk to restore the Geneva movementto its original position therein.

aaeasrs adapted to be variably rotated and power actuated means for variably rotating the same. a

clutch in said transmission connection includlnz a manually retractable pin on the power actuated side or said clutch and a disk having a cam face aflording a throated entrance to a notch adapted to receive the pin when the parts are clutched, and manually operated means for rotating the condenser when the transmission connection is unclutched and for rotating the cam 'faced disk therewith, the engaging of the clutch elements serving to cam the disk to position to receive the pin and restore the condenser element to a position corresponding with that occupied by the pin.

' JOSEPH L. SWALLOW. 

